A low drop-out voltage (LDO) voltage regulator circuit has industry applicability in the field not limited to mobile devices such as smart phones, laptops, video camcorders, and other electronic devices that may relied upon a battery in order to operate. The LDO voltage regulars would ensure such electronic device to require a low voltage and low current so as to function efficiently and with a low power consumption.
An LDO voltage regulator circuit typically has an error amplifier electrically coupled to a pass element, a feedback circuit, and a compensation circuit. The error amplifier typically receives, through an input terminal, an input voltage which is amplified by the error amplifier as an amplified voltage. The amplified voltage is received by the pass element which could be but not limited to a power transistor which would generate an output voltage to drive an external circuit. The feedback circuit would receive and subsequently scale down the output voltage. The scaled down output voltage is sent back to the error amplifier as a feedback voltage. The compensation circuit may include one or more compensation elements to provide a control mechanism to enhance the performance of the LDO voltage regulator. The power mechanism could be implemented by, for example, a Miller compensation circuit.
In a typical LDO voltage regulator circuit, a local common mode feedback circuit and a Miller compensation circuit could be utilized for providing feedbacks and current compensation. However, a Miller compensation circuit may exhibit a slower transient performance as well as an unstable output relative to other methods. Such output perform could be undesirable as excessive ringing and slow transient performance may cause the load to malfunction. Therefore, an LDO voltage regulator circuit that has a better output transient performance as well as a better output voltage stability would be desirable.